Trident maple tree named ‘ABMTF’

ABSTRACT

A Trident maple tree ( Acer buergerianum ) named ‘ABMTF’ having an upright oval canopy, dense branching, smooth bark that has minimal exfoliation, and vigorous growth rate, and is capable of being reproduced reliably from vegetative cuttings.

Latin name of genus and species: Acer buergerianum.

Variety denomination: Trident maple tree which I have named ‘ABMTF’.

BACKGROUND OF THE INVENTION Discovery

I discovered my new tree in a nursery production field of Trident maplespurchased from a nursery in Florida that provided these trees as arandomly open-pollinated Acer buergerianum seedlings during the winterof 1995. This group of seedlings was grown in a liner field and thentransplanted to an adjacent production field in Loganville, WaltonCounty, Ga. during the winter of 1996. It was here that I discovered theclaimed cultivator ABMTF.

Propagation

‘ABMTF’ was asexually propagated by the method of vegetative cutting atmy direction in the summer of 2000 at Moon's Tree Farm in Loganville,Ga. Softwood cuttings three to five inches long were treated with3000-ppm potassium indole-3-butyric acid (KIBA). The cuttings were thenplaced in peat pots filled with horticultural growing media and thenintermittently misted for a period of five to six weeks. Currently oursuccess rate for this method exceeds 90%.

Uniqueness

Seedling Trident maples are very diverse due to genetic variability inleaf size, branch structure, bark exfoliation and growth rate. My newtree was notably different from others in this seedling block due to itsvigorous growth rate, dark green foliage, symmetrical branch structure,smooth, straight trunk and drought tolerance. These characteristicsclosely mimic the qualities found in larger maple species. Thisinvention has not been observed under all possible environmentalconditions, but the progeny of ‘ABMTF’ have repeatedly shown that thesecharacteristics are genetically stable.

Use

‘ABMTF’ has been observed for several years, and I believe it to be veryuseful for urban street plantings and commercial sites where a droughttolerant, medium-sized maple species is required. Nursery producers willalso benefit from the increased growth rate and uniformity.

SUMMARY OF THE INVENTION Background

Acer buergerianum is an oval-rounded to rounded small maple native toChina. It performs well in the more acidic soils of zones 5 to 8 in theUnited States. It has been successfully grown from the mid-Atlantic areasouth to northern Florida and west to the eastern part of Texas andOklahoma. I expect my new variety of Trident maple to perform as well asthe species in these regions.

Industry Representation

Trident maple is typically seedling grown through randomopen-pollination. This method creates great variability of canopy heightand width, branch structure, leaf color and size, and bark exfoliation.This genetic diversity has limited the landscape use of this tree due toa lack of uniformity. Presently, the only commercially availablecultivar of this species of which I am aware is Acer buergerianum‘ABTIR’ Streetwise, U.S. Plant Pat. No. 9,576. This cultivar has agrowth rate greater than seedling grown trees, early exfoliation, andgrayed-purple fall foliage.

My new variety differs from ‘ABTIR’ Streetwise, U.S. Plant Pat. No.9,576 in the following characteristics, (1) a more rapid rate of growth,(2) different branch characteristics, and (3) bark smoothness. Accordingto the description of ‘ABTIR,’ this tree reached a height of eighteenfeet after eight years. My new variety ‘ABMTF’ grew from a twelve-inchseedling in the winter of 1995 to a height of twenty-one feet and aspread of thirteen feet when it was transplanted in November of 2000 (aperiod of 5 years). The angles of the primary and secondary branches aremore distinct and the ends consistently roll upward. Finally, the barkof Streetwise is fluted and exfoliates at an early age whereas ‘ABMTF’has a very smooth bark and has less exfoliation.

DESCRIPTION OF THE PHOTOGRAPHS

The accompanying photographs illustrate this new Trident variety withcolor as true as reasonably possible in this type of color photography.

FIG. 1 is a photograph of the claimed cultivar taken in the summer of2001 at an observation area showing form and habit. The tree is sevenyears old.

FIG. 2 is a photograph of the claimed cultivar taken in the fall of 2001showing variations in fall color and branch structure. The tree is sevenyears old.

FIG. 3 is a photograph of the interior canopy of the claimed cultivar.

FIG. 4 is a photo of the bark of the claimed cultivar at six-inchcaliper showing color, smoothness, and minimal exfoliation.

FIG. 5 is a photo close-up of fall foliage and variation of color.

FIG. 6 is a field row shot of progeny at two-inch caliper.

FIG. 7 is a photo of summer foliage showing leaf shape.

DETAILED DESCRIPTION Botanical Description of the Plant

This invention has not been observed under all possible environmentalconditions. The phenotype may vary with variations in growingenvironment, without, however, any variations in genotype. ‘ABMTF’ iscurrently being grown in fields adjacent to 6327 Hwy. 20, Loganville,Walton County, Ga. This particular area of Walton County has a clay loamsoil type located in USDA Zone 7 and has an average rainfall of 30-60inches annually. The following is a detailed description of ‘ABMTF’Trident maple at age seven with color terminology in accordance with TheRoyal Horticulture Society (R.H.S.) Colour Chart, except where thecontext indicates a term having its ordinary dictionary meaning.

-   Parentage: Chance seedling random open-pollinated Trident maple    parentage purchased from supplier in Florida.-   Propagation: Genetically stable characteristics reproduced through    asexual, vegetative softwood cuttings.-   Locality where grown and observed: City of Loganville, County of    Walton, State of Ga.-   Size and growth rate: At time of transplant, the new tree was five    years old and measured 5.5″ caliper at 12 inches above the ground.    The height was 21 feet and the width was 13 feet, thus providing a    height to width ratio of 1.61. Prior to transplanting, the tree had    an average growth rate of 1.25″ caliper per year. This same rate of    growth has been evident in the progeny.-   Vigor: In field test on liner stock, my tree, ‘ABMTF,’ was grown    next to ‘ABTIR’ and seedling material. With the same environmental    conditions ‘ABMTF’ was 30% larger than the seedlings and 10% larger    than ‘ABTIR.’    -   -   Tree shape.—Upright oval with very dense foliage.        -   Trunk.—Smooth and unfluted with minimal exfoliation. Some            stripe detail is evident which causes the coloring to vary            between greyed-green (RHS 197A) and greyed-brown (RHS 199D).-   Branching habit: More dense than species, primary lower branching    emerges at about 10 to 15 degree angle with 20% of branch end    curving upward. Branching toward the top third of the tree has 50 to    60 degree angles.-   Branches: Hardwood branching has a greyed-green (RHS 197B) coloring    while soft wood branching is yellow-green (146C). Wood is rigid but    smooth, with small greyed-white lenticels.-   Foliage: Mature leaves are semi-gloss tri-lobed with each lobe being    triangular. Width between outer lobes averages two to three inches.    Distance from base of leaf to middle lobe is also two to three    inches. Margin of leaf in lobe section tends to be slightly serrate.    The color of the leaf front is a dark green (RHS 139A) while the    backside is a greyed-green (RHS 189A). As new growth emerges, the    coloring is a greyed-red (RHS 178A). During the fall, foliage is    varied between yellow-orange (RHS 20B) through a greyed-red of (RHS    179B). The petiole is a yellow-green (RHS 146C), measures about two    inches and is smooth.    -   -   Buds.—Conical, reddish-brown (RHS 176C), ¼ inch long and            pyramid.        -   Stems.—Slender, grayed-brown (RHS 199D) with pubescence.        -   Flower.—Small, greenish-yellow (RHS 145B) in slightly            rounded clusters during mid-spring.        -   Fruit.—Yellowed-green (RHS 144C) double samaras ¾ inch to            one inch long and ¼ inch wide, formed in autumn.        -   Disease and pest.—During the evaluation period, I have not            seen disease or pest damage on the parent or the progeny.        -   Hardiness.—USDA hardiness zone 5-8.

1. A new and distinct variety of Trident maple tree (Acer buergerianum)named ‘ABMTF’ substantially as illustrated and described herein.